Well I don't know the answer, but I know why airplanes require oxygen. As a pilot, it's been drilled into me that over about 12000 feet, hypoxia can impair judgement and you can pass out without warning. When a plane suffers decompression, the first priority is to get down to a safe altitude ASAP, and you give people oxygen to keep them alive while you do it.
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Mike DunlaveyMay 10 '11 at 1:45

I don't think I have a definition for "high enough" :)
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Monkey TuesdayMay 10 '11 at 4:20

7

Never get your science facts from a fictional character. And that goes double for alter egos.
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zeteticMay 10 '11 at 6:18

The oxygen in emergency-airplane masks wont get you high, those dont have more oxygen then normal air. Oxygen masks that get you high are used on patients to keep them calm under operation, if you used such a mask during a plane crash you wouldnt panic.
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user1708May 10 '11 at 11:09

@JOHA: Not quite true. The emergency air provided is 100% oxygen, whereas atmospheric oxygen accounts for only 21% of normal air. So there could be a difference.
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Thomas OMay 10 '11 at 12:16

The brain requires a constant flow of oxygen to function normally. A hypoxic-anoxic injury, also known as HAI, occurs when that flow is disrupted, essentially starving the brain and preventing it from performing vital biochemical processes. Hypoxic refers to a partial lack of oxygen; anoxic means a total lack. In general, the more complete the deprivation, the more severe the harm to the brain and the greater the consequences.

If you don't get oxygen, you will most likely pass out and then you won't feel anything at all. As a matter of fact, the higher you go, the faster you will pass out.

The conditions of the windows are consistent with a loss of pressurization and a subsequent rapid drop of temperature. It is likely that the pilots and occupants may have lost consciousness due to hypoxia, or a lack of oxygen.

Incidentally, if he had been on a USAF C-21 (Lear35 variant), that accident most likely could have been prevented with the way their pressurization system works.

Pure Oxygen?

As to breathing pure oxygen, it does not get you "high" in any way. Consider that oxygen masks are deployed when the pressure is low, you actually need more oxygen to actually get into your blood stream. NASA would employ a trick of using less atmospheric pressure in their capsules, and having the astronauts breathe pure oxygen. That practice was mostly stopped after the Apollo 1 Accident.

Spacewalkers must wear pressurized spacesuits in order to work in space. These suits have pressures significantly lower than ambient cabin pressure of a spacecraft. This makes spacewalkers subject to decompression sickness, more commonly known as the "bends." Decompression sickness results from nitrogen bubbles forming in the tissues or blood stream and moving to other areas of the body. Therefore, spacewalking crewmembers must perform a pre-breathe protocol, which is designed to wash out any excess nitrogen from the body, before a spacewalk. This protocol takes advantage of the fact that exercise increases the speed at which nitrogen is removed from the body by increasing blood circulation through the extremities. The ISS pre-breathe protocol involves breathing pure oxygen for a total of 2 hours and 20 minutes and includes a short period of high-intensity exercise at the beginning of the pre-breathe procedure.

Station astronauts begin the pre-breathe protocol by exercising vigorously on the space station's cycle ergometer for a total of 10 minutes while breathing pure oxygen via an oxygen mask. After 50 total minutes of breathing pure oxygen, including the 10 minutes initially spent exercising, the pressure in the station's airlock will be lowered to 10.2 pounds per square inch, or psi [or 703 hPa]. During airlock depressurization, the spacewalkers will breathe pure oxygen for an additional 30 minutes. At the end of those 30 minutes, with the airlock now at 10.2 psi, the spacewalkers will put on their space suits. Once their spacesuits are on, the spacewalkers will breathe pure oxygen inside the suits for an additional 60 minutes before making final preparations to leave the station and begin their spacewalk. This protocol provides a total of 2 hours and 20 minutes of pre-breathe time, including the 10 minutes of vigorous exercise at the beginning of the procedure.

I should hope those guys aren't high up there (in the sense of mental impairment)!

As a pilot, I have breathed 100% oxygen many times as well, and I can anecdotally report that if it is supposed to make you high, I am sorely disappointed in the feeling.

If so, is the effect strong enough to keep the average person placid during a plane crash?

Oxygen on planes is not to get you high or to keep you placid. It is there to compensate for the lack of oxygen due to loss in cabin pressure at higher altitudes. From the very first comment on your question:

When a plane suffers decompression, the first priority is to get down to a safe altitude ASAP, and you give people oxygen to keep them alive while you do it.

The time of your exposure to pure oxygen in an aeroplane is very short for you to suffer oxygen toxicity. But if the exposure is prolonged, you may suffer oxygen toxicity.

So, Tyler Durden was only half right: Oxygen does get you high, but it's not why they put in on planes.